The present invention relates to an apparatus for sensing the magnitude and intensity of solar radiation, especially a sensor for detecting solar radiation incident upon a vehicle which includes a controller for adjusting the air conditioning in response thereto.
Solar radiation sensors have become popular for providing sensory input into automobile air conditioning systems that include means for separately controlling different areas within the passenger compartment. Some of these sensors include only two photodiodes, and roughly separate the solar radiation load and the passenger compartment into halves. These sensors may not provide sufficient resolution of the radiation load for some consumers. Yet other radiation sensors provide four photodiodes for improved resolution of the radiation load into quadrants, but mount the photodiodes on angled surfaces. This angled mounting results in more costly and less reliable connections from the photodiodes to the corresponding conditioning circuitry. Further, some of these quadrant radiation sensors have excessive cross-talk onto one of the photodiodes from adjacent quadrants, and measure this cross-talk along with the radiation load of the correct, corresponding quadrant. This excessive cross-talk can result in poor overall system performance because the sensor includes too much averaging among the quadrants. A further drawback of some radiation sensors is the remote mounting of the conditioning circuitry from the photodiodes, with corresponding reliability problems. This latter drawback is especially apparent for those sensors which are mounted on parts of the vehicle where the sensor and conditioning circuitry cannot both be accommodated.
What is needed then is an improved solar radiation sensor. The present invention provides such a sensor in a novel and unobvious way.